Waters Mingled Together
by Trilies
Summary: Mer/Pirate AU. All Gokudera wanted was for Yamamoto to not accidentally seduce one of the mer. Unfortunately for him, by the time he thought to give this particular order, he was already far too late. Whups.


**Author's Note**: Warnings for sexual content, of the xenophilia variety

* * *

"Hey, idiot!"

Gokudera's voice had a penchant for reaching through every inch of the ship, which was valuable for someone acting as the quartermaster on the Vongola. So he was 100% sure that Yamamoto heard him from where he was leaning against the ship's railing. Yet the bastard had the nerve to not even look at him? Gokudera bit back some of his temper. It was something he was working on. Right now, he had to focus on the more important things, so he settled right besides Yamamoto with one elbow on the railing and a finger in the man's face. "We need to talk about your shitty flirting habit."

"Mmhm," was the only response. Yamamoto continued not to look at him, instead staring pensively out into the sea. Longingly? Maybe they'd been landstuck for even longer than Gokudera thought if this idiot was so interested in getting back to open water. That didn't change the fact of the matter, which was that they had to deal with Yamamoto being so damn charming that he practically caused a scandal whenever they hit land. And he didn't have to _try_.

Gokudera couldn't see the appeal in an empty headed idiot who smiled all the time. Or maybe he just aggressively refused to. If he did, that would almost be something like _losing_.

He forged on, determined to slam through Yamamoto's thick head. "We're on the edge of mer territory. You paid attention when we were all talking about that, weren't you? So I am going to _need_ you to not accidentally fuck any of them, purposefully fuck any of them, accidentally seduce any of them, _or_ purposefully seduce any of them. Literally any of them, but _especially_ anything poisonous. Got that?"

Yamamoto was still not moving. The meaning of this was slowly creeping onto Gokudera, and hammered right in when Yamamoto sort of laughed. "Ha ha. So, it might be a little late for that." He was still smiling.

Frozen from the sheer fucking impact of that, Gokudera slowly looked Yamamoto over. And then he swore. Violently. 

* * *

It was a common misconception that mer had territories. Or, rather than a misconception, it was something more like an over-generalization. After all, wasn't that similar to saying that all mer were exactly the same? That wasn't even physically true, with how some had the shimmering scales of rainbow colored fish while others held the smooth skin of dolphins and then even more others held the terrifying maws of a shark to match their sandpaper fins. To say all those were alike was kind of silly, and that was the least such thoughts could be called.

Yamamoto had learned this a long time ago from his father, when he'd done trade with the shimmering golden koi mer who lived in the rivers near to their little fishing village. Honestly, he was fairly certain it was common knowledge among most navigators. Especially navigators who didn't exactly follow the law, honestly. Navigating the open seas was difficult as it was, and pirates couldn't exactly just buy sailing charts with any ease. However, for those who lived within the waters of the world, whether the immense seas or the deep rivers... Yamamoto didn't know exactly how, but he knew that just about most mer had a good understanding of how to read the stars to get them to where they needed to go.

He'd be a liar if he said that he had never in his entire life inquired with a mer on where he was, honestly. Mostly when he was younger, ocean air still too thick of salt for his tongue and his head swimming every time he was on the deck of a ship. In more recent days, he liked to think he knew the ocean and the stars well enough to guide things on his own. However, no one ever asked where he had learned his skills. That Yamamoto had them at all was good enough for most people.

But how could he forget those who had helped him so much?

Maybe it was just the cultural differences, too, but he had an easier time of dealing with mer than people of his own race sometimes. That probably would have been strange to hear, for most people who knew his name or face. How could _he_ of all people have difficulty talking to or dealing with others? He was handsome, athletic, friendly, and a whole other bunch of positive adjectives. Yet as he grew up and his relationships never seemed to change, Yamamoto began to wonder if anyone was ever looking past that laundry list of good traits, and if anyone even wanted to. Would they be fine with how handsome he was if they knew he was more stubborn than anything? Would people accept his friendliness if they knew it was sometimes a veneer for mocking, or teasing?

Mer never gave him that feeling. Maybe because they were so detached from the regular life that he lived, he could see them as something different, even if they weren't actually that way. Yamamoto had that particular realization not too long after he first truly got to know Tsuna, when they were taking their first journey out onto open waters. It took him a little while longer to realize that it was okay if his view of things had been slightly different than the reality of the situation.

That couldn't change the feelings he'd had because of them. That couldn't change how important they had been to him for so long. So Yamamoto kept an eye out as him and Tsuna traveled across the seas, crew growing bit by bit. He watched the stars to guide them, and then he watched the ocean for hints of shapes that were his own connection to home. Maybe some mer had territory, but other mer? Other mer you could find everywhere.

Sometimes even where you didn't expect them. 

* * *

The first time that he had seen the mer, he had been mildly intoxicated and it had been night. That meant, for the first five minutes, Yamamoto hadn't even the faintest idea of what he was looking at. Five minutes before _that_, and he hadn't even realized there was anything to look at, honestly.

Instead, he'd been focused more on keeping his legs straight underneath him, an endeavor he'd ultimately given up on. Only a few feet from the docks where the Vongola was anchored at, and he'd slumped against a lamp post with his eyes fluttering shut for a brief moment. Being drunk sometimes felt not unlike being underwater. There was a peculiar sort of sluggishness in his brain, similar to trying to punch the ocean. Everything was familiar while simultaneously new. Still. If there was one thing that the ocean had over being drunk, besides the benefit of not including nausea along for the ride, it was that it at least had the decency to be cool.

Drunk to this extent, Yamamoto found that everything was just too damn warm. Even the pole seemed to carry leftover heat from the daytime, sticking to his skin in a way that left him sickly. Wobbling slightly, he pushed himself up straight and forced his eyes open. Behind him, he could still hear the distant sounds of ruckus and laughter that spilled forth from the bar. The ocean before him seemed to absorb all of it silently, without complaint. That was a lie in its own way, too, he was pretty sure, much like it was a lie of his own when he did stupid shit like let someone buy him a drink despite his actual zero interest in alcohol. His problem, Yamamoto figured, was that he went with the energy too much sometimes. He got caught up. That wasn't always a bad thing, mind. Getting caught up in Tsuna's own issues was how he'd ended up where he was: the happiest he'd ever been, with people he felt he could actually connect to properly, in a life where he tasted a challenge as much as salt when they were sailing.

But alcohol. Ugh.

A bottle was still in his hand, simply because it hadn't occurred to him to set it down on the way out. That left one hand free to drag down his face, pulling lightly at his lower eyelid. He was still looking out to the sea. Even as it took in all the light and sound of the port town, it was so very dark. Nothing penetrated past those deep waves beyond a surface level, the light stuck on the ever shimmering surface, a pale film of blues and greens and purples that hardly seemed tangible...

Wait. Yamamoto paused, blinking a few times before he narrowed his eyes into a squint. Lights weren't blue, green, _or_ purple. Not normally, anyway. There weren't a lot of lights lit in town, being dark as it was. The closest thing it had were a handful of streetlights, with not even most of them alight, including the one he was leaning against in that moment. Certainly, there were the pubs and inns and more _night time friendly_ leisure businesses that were thriving, but those weren't near the docks where lots of people would first get a glimpse of the town. Those were deeper in, their brightness hidden away from the ocean. That left only the lonely moon drifting slowly past the stars.

Seamen had lots of superstitions about the moon, something Yamamoto had learned fairly quickly the more he began to hang out with them. The moon held influence over the sea, after all, and it was often part of how they could find their way when all else seemed endless on the water. When it changed to a pale silver or arrogant gold or wary red, well, everyone had something to say about that. Yamamoto had eaten it all up, fascinated with perfecting the job he'd chosen alongside Tsuna. That meant he knew that the colors he was seeing weren't anything like those he knew the moon was capable of giving.

Most people would take that as a reason to back off, not wanting to mess with any of the many dangerous mysteries which the deep waters of the ocean held.

If Yamamoto had that kind of sense, he wouldn't have become a pirate.

Fascinated and at ease from the familiar smell he'd had with him all his life, he stepped closer and squinted. The world tilted, crossed over itself and made his brain spin in his skull, a fact he just had to deal with for the time being. None of it _helped_. If anything, it almost made him think for a split second that the shape on the water was someone's sheet that had fluttered off a line or something and had gotten ensnared by the water. That was stupid, however, and he tossed the idea to the side almost immediately. Even drunk as he was, Yamamoto knew how things moved on the water, and bed sheets didn't... _pulse_. Clearly he couldn't rely on seeing from this distance. A little bit excited and grateful, somehow, he made his way to the slight stone wall separating the beach portion of the dock from the rest of town. That he didn't slip and eat a face full of sand was half a miracle and half that, even completely hammered, he was still athletic as all hell. Including with a bottle in one hand.

Once he was close enough that the water was licking at his boots, it was considerably easier to discern the exact shape of the creature. Mostly, that it was translucent, a sort of thin film... And something a lot more _solid_ right in the center of it. There were a lot of round things that could go floating in the ocean, like coconuts, but they didn't usually have a pair of eyes that focused directly on him with a film over _that_ which reflected light right back as they stared.

Yamamoto didn't _smile_, because he'd come to learn that meant a very different thing with mer until they got to know you. He just grinned and waved with one hand. At some point when he wasn't paying attention, his legs had moved him a little further into the water. "Hey there," he said cheerfully. "Nice night, isn't it?"

There was no immediate response, only more silent staring. At the edges of the bell, something seemed to shift and tug. Belatedly, his brain finally pieced together what was so familiar about this scene. Still, Yamamoto didn't step back, or stop. Instead, he waited another beat. "I could try another language," he said, and then tried a few anyway. He only really knew a couple pretty well, counting his home tongue, but he'd managed to come across all sorts of different scraps of languages, enough to sort of introduce himself or show that he didn't mean any harm. Just because Haru was a lot better at it than the rest of them didn't mean he couldn't _try_.

Still nothing. His arms were still above the water, so he would be fine at initial contact, he just preferred they not get to that point. Fingers wringing around the bottle, he remembered its existence. Hey, what the hell, right? Still grinning, he stretched out his arm towards the shape. When they got so close, he had no idea. Being drunk was kind of a pain in the ass that way. "I don't think I'm going to finish this. I'm Yamamoto. Have you had a drink before?"

At first he thought that he'd continue to get silence, which was probably a pretty awkward thing at _best_, except then the head in the middle of the jellyfish bell finally moved. It wasn't a _lot_, objectively speaking, except that anything was really a lot when there'd been absolutely zero response before. In the moonlight, this close, it was easy to see the humanoid face that tilted back to look at him properly. Mer could be quite varied, almost more than humans could be... and Yamamoto had never seen any of them that were quite like this. As a general rule, although it only counted around half the time, mer had something like human skin on the 'top' half, or, at the very least, they looked a good bit more human than they didn't waist up. For this one? They weren't all the way translucent as their bell was, just... _thin_. Thin like holding paper up to the sun and seeing the sunlight turn map tan into something golden, moonlight turning ship sails aglow. Yamamoto had no idea where the light was coming from, how much of it was reflective and how much of it might have been something from within them, only that it was stunning. It somehow seemed to show even more in the mer's noticeably plump limps, and the eyelashes that curled up along their eyelids. Well. Where they would have eyelids. Mer could be weird in what they did and didn't have. Matching this radiant beauty, the mer asked, "You're intoxicated, aren't you?"

"Probably more than a little," Yamamoto answered honestly, because he might hide a lot of things about himself but he wasn't an actual liar. Besides, the bar smell was probably clinging to him. "Would it make you feel better if I told you that I probably would have done the same thing if I were completely sober? I'm just not sure if I would have gotten here sober, at this particular time of night."

"Not really." The edges of their bell twitched again; Yamamoto didn't feel anything pressing in against his clothing or slipping underneath it. He'd take that as a victory. "I could drown you right now."

"Ha ha, lots of people say that about me!"

"...I mean it."

"They also say that." They weren't usually creatures of the ocean, but they did also say that. Pulling his hand back, Yamamoto tilted his bottle to the side in... some sort of gesture. He wasn't really sure of the meaning himself. "Do you want to?" Exactly like before, there was no quick response, and Yamamoto was starting to wonder if perhaps that's just how this particular mer was instead of it being a legitimate threat. Of course, it might also have been a legitimate threat. Used to that sort of thing, Yamamoto determinedly carried on. "How should I refer to you, anyway? By, uh, sex, or gender. That sort of thing. A name would also be good but I don't mind if you don't want to tell me that!"

It was a good question to ask. A lot of people dismissed the mer as being 'weird', if occasionally helpful, but Yamamoto was pretty sure that was just the generalization problem coming up again. Gender was one of those 'weird' things about mer, although Yamamoto found it pretty simple. Some mer changed due to conditions. Others just changed because they could. Others never changeed, while also still changing. All anyone ever has to do was ask. Until that point, Yamamoto liked to claim no idea, being that it was true. Besides, with every mer he'd ever talked to, it seemed like it was appreciated.

Considering the careful way this mer looked him over, Yamamoto had to wonder if it was appreciated or if this one had never really dealt with humans much at all. Just because they lived near a human town didn't really mean anything. "Male," the mer finally said, and Yamamoto grinned widely. "Chikusa."

"Chikusa," Yamamoto repeated, rolling the name around in his cheeks. It was short and blunt against his teeth, an anchor impact into sand. He liked it. "Nice to meet you. I'm Yamamoto Takeshi. Or, ha ha, Takeshi Yamamoto depending on where you're from? I guess it doesn't really matter for you. So, Chikusa, what are you doing?"

Chikusa's lips thinned, which didn't really actually do anything for how full they were except that Yamamoto wasn't sure he could call it an outright frown. "...Tell me what you're doing first."

"Yeah, that's fair, isn't it? Ha." If he was the one asking all the questions, then it was sort of a one sided conversation, and it gave him an advantage besides. Taking a deep breath, he let his boots slide against the sand beneath his feet that he couldn't see until he was lulling backwards with water lapping at his jaw. "I guess I was getting away. People can be really tiring, you know? Ha. I mean, not my crew," he said, quickly correcting himself. "It would be pretty bad if I couldn't tolerate my crew! I mean, we're all kind of stuck together for days on end. I'm really glad I managed to find Tsuna when I did, because the rest of the crew is- I mean, they're not exactly like I hoped, because I wasn't hoping anything in particular? But nothing is boring. And we're all pretty honest! So _that's_ always exciting."

Getting a whole chest of issues in only a few sentences was apparently not what Chikusa signed up for tonight, since, when Yamamoto turned his head to look at him, he was staring at him with those wide eyes. Turned away from the moon, and they looked much darker with the irises more defined. "So do you hate people or not...?"

"I don't hate people!" Yamamoto protested. "They're _interesting_. But most people just require... a lot of work, you know? Or I guess you might not."

"...I don't do anything... that I'm not interested in."

"Ha ha. I'm jelly." Almost immediately he laughed at his own joke, convulsing and curling in on himself until ocean water washed up into his mouth as a firm reminder of where the hell he was. Once he was done sputtering, Yamamoto glanced over at where Chikusa was floating. Promptly, he revised his theory that Chikusa didn't talk to humans very much. The mer was giving him such a flat look that there was absolutely _no doubt_ that he had heard the same joke perhaps dozens of times before. "But anyway, yeah. I guess I had enough! So I was coming back to the ship, except then I saw you, so I thought I would come say hi."

"...Even though I could kill you."

"You haven't yet!" Apparently there was nothing Chikusa could say to that, so Yamamoto turned the question right back around. "So what are you doing?"

For a moment, Chikusa only observed him where he was partially floating in the water with his feet only partially anchoring him and his bottle somehow still in his hand. Apparently, that was enough of a mental image for him to come to a conclusion that honesty would be an alright policy instead of leaving, or killing him. They'd only known each other for a few minutes, but that was enough for Yamamoto to have a decent gauge on the mer's personality. He didn't seem like the type to lie. That impression was only strengthened when Chikusa said, "I was going to poison a couple of ships."

"Huh," Yamamoto said, with less worry than perhaps other people would feel at such a statement. A minute later, and it occurred to him to ask, "Which ones?"

This time, there wasn't any hesitation before the answer came. "The one with the man in armor figurehead... the military vessel... and the one with the clam decorated on its side..."

While it was probably more than a little cruel to say as much, Yamamoto didn't pay much mind to the first two ships that Chikusa listed. The military vessel had been there before they'd docked just the other day, and his crew had already been pretty hasty in getting everything done they needed to so that they could set sail again. As far as any of them had been able to tell, there were only rumors floating around about them, and they weren't yet as infamous as some of the other pirate crews sailing across the seas. Still, why tempt fate, right? Since they were natural enemies, Yamamoto wasn't exactly sure if he had it in him to exactly feel heartbroken over the idea of them being poisoned by some mer with an agenda. The same could be said for the other ship Chikusa had just described as well. Yamamoto hadn't gone on it or anything like that. He wasn't even particularly familiar with its crew, only that he had seen them at a distance. However, in some ways, he didn't really need to do so. On his own, he had picked up the secretive way the crew packed their luggage, their furtive glances, various little things that made them more untrustworthy for anyone who was actually paying attention. More than his own senses, however, he trusted how his crew had reacted: Tsuna's uneasy fidgeting whenever he saw the ship or its crew, the way Gokudera spat in its direction as if he saw something he didn't like, even Lambo's simple blunt complains of "Wow, what a bunch of creepy guys!" Whatever they were hiding in their shipment was something unsavory. Yamamoto had little doubt about that. Perhaps this mer had seen something even humans hadn't seen just yet.

So that was all, well... Yamamoto couldn't exactly say it was "fine and dandy". It was just, at the very worst, it would help him and his out more than it would harm them, he was pretty sure. One thing wasn't great, however, and he blinked over at Chikusa. "Hey, the clam ship is my ship. I mean. Tsuna's ship. I'm a part of his crew."

Chikusa didn't particularly react, besides blinking back. "So?" he asked plainly, which... Well. That was fair, wasn't it? Yamamoto couldn't exactly complain about the fairness here. After all, no one could trust the military or navy or anything else to do with the government, and the ship with the armored figurehead was clearly suspicious... And then there was the Vongola, with its crew of actual pirates.

It was really a probably more fair assessment than Yamamoto was giving other people. "I mean, can I at least ask why you're trying to poison our ship?" he asked, fumbling to regain his footing. It was a little hard when he was still drunk and fighting against the tide.

Apparently this was enough to get the mer to pause, eyes narrowed as he watched Yamamoto. Only when the pirate wasn't making any moves towards him, just awkwardly float-standing in the water, did Chikusa ease up again for an answer. "You're pirates," Chikusa said bluntly, which. Like Yamamoto had said. That was fair. He couldn't argue against that. "You kill and steal from people, so you're better off dead."

Okay, _that_ he could argue with. Yamamoto raised up one finger with the only hand he had available. "Alright, so, what if I. What if we didn't steal from anyone who didn't have it coming? And we do minimal killing. I'm really proud to say we do minimal killing because Haru is really a great shot with the cannons, and Tsuna is pretty stern about stuff like that! Besides, I mean, if killing is bad, you're still killing people with your poison, right?" Chikusa thinned his lips again, and Yamamoto's own grin widened. "So there have to be... exceptions!"

"I'm not arguing with a drunk human..." Chikusa turned his head to the side, a movement which sent his bell trembling. "Not without Mukuro..."

It didn't occur to Yamamoto to ask just who Mukuro was. Instead, he just cheerfully held out his bottle again. "We don't have to argue. We can do a trade. I'll give you this to drink- I didn't even get halfway on this one, look- and you hold off on poisoning everything, just for tonight!"

"...Why are you assuming I would even like that kind of human drink..."

"Have you ever tried it before?" No answer. Helpfully, Yamamoto plugged his thumb over the open bottle. "Here, this way it won't get watered down." Apparently, that was the way to do things. Chikusa finally shifted forward, the bell still acting as a barrier between the two of them, and he managed to slip his hand underneath the rim in order to retrieve the bottle from Yamamoto's hand. The entire time, he kept carefully still. He'd spent all this time doing his best to convince the mer not to kill him on purpose. It would be fairly embarrassing if he managed to get himself stung _accidentally_. Chikusa even plugged his thumb over the top as Yamamoto had done, keeping it that way until he had it to his mouth and took a very small sip.

A pause.

Chikusa's following narrow eyed glare was almost accusatory, and in a way that Yamamoto knew quite well. It was the same kind of look Gokudera gave him whenever he managed to navigate them quickly and efficiently, not wasting even a bit of their effort. From that alone, he felt pretty triumphant, and that feeling remained even as the mer rippled backwards before disappearing down into deeper waters. Yamamoto let him, standing there in the water for a little while longer to enjoy the feeling of waves washing against his body. Only a little while longer. Eventually, he had to drag himself out again. Having disappeared from the ruckus at the bar was one thing, but if Gokudera found him passed out in the water, halfway out to sea?

Boy, would that be embarrassing. 

* * *

"So thanks for not poisoning us!"

Somehow, for whatever reason, that seemed to annoy Chikusa a little bit as he stared up at Yamamoto from deep within the water. The Vongola had set sail the very next morning, as soon as it was confirmed that everyone was sober. He hadn't checked for himself what had happened with the other ships, or even their own stocks. For the former, he didn't really care, and for the latter, well, that was what they had Lambo for. Lambo was the youngest out of all of them, a teenager who couldn't really even be called a man. On any other ship, he'd be a cabin boy or a powder monkey. On the Vongola? Here, he was the one in charge of making everything that kept their most valuable items, whether they were for sale or, more often than not, for health and eating. It seemed like a pretty big task for a kid Yamamoto could remember whining about sea sickness and wanting sweets, but he'd adapted to his new role well. They all had. So if Lambo had looked over their provisions and given the all clear, then Yamamoto was willing to trust in him just like he trusted everyone else on the ship.

Considering he was still alive and breathing, he considered that trust well placed.

He had no idea how Chikusa was able to float so easily alongside the ship as she sailed, so he didn't really think too hard about it. Instead, he tilted his head to the side as Chikusa raised a question up to him. The mer spoke so quietly that it really took a lot to hear him from such a distance. "Do you really think we're anything alike?"

Yamamoto considered the question for a brief moment. "Probably not," he answered, unable to tell Chikusa's expression with how far away they were from each other. "I mean, even if we're doing the same thing, it could be for entirely different reasons, right?"

Once again, he seemed to surprise Chikusa. The mer stared up at him for a while longer, those eyes still shimmering and reflective at night, before his pale colorful body dipped back into the waves. That was fine. Yamamoto had a feeling that if he had bothered to follow him this far out to sea, Chikusa would show up again.

Credit also had to be given to Kyoko, from where she kept watch high up in the crow's nest. In the daytime, Haru kept lookout, but nighttime was Kyoko's preferred hours for when she wasn't working as a carpenter alongside her brother's boatswain duties. At night, the sort of thing she kept an eye out for were a lot different from what Haru had to deal with... and that difference in duties, Yamamoto had come to realize, meant she was a lot more in tune with things that happened down on the deck. Despite this, she never said anything about who he talked to that night when they were still only a day away from port. She continued to not say anything even when it happened again and again.

Not that they came all at once or anything. Apparently, only the vulnerability of Yamamoto being piss drunk had been why Chikusa held a prolonged conversation with him the first time. With him sober, a lot more caution was employed for quite a few of those first nights. More often than not, Chikusa would ask one question, listen to an answer, and then disappear back into the waves for the next nightfall. By that point, sometimes he'd ask a follow up from their "talk" from before. Other nights, he went with something entirely different. For the most part, he actually seemed almost content with merely listening to Yamamoto talk no matter how off-tangent he went... which meant, of course, that Yamamoto went off-tangent often, extending the one-sided conversation for as long as he could.

The first night Chikusa actually stayed, responding to some dumb story Yamamoto had told about an old fisherman's tale about a crew gaining a mysterious new passenger after sailing through haunted waters, he'd smiled. And Yamamoto smiled all the time. 

* * *

Chikusa didn't really speak much about himself, and Yamamoto didn't really ask, save for when he double checked on if the mer was familiar with a certain human concept or item. He didn't know where Chikusa came from, or pry into why he was perfectly fine with following after a pirate ship whose destination he didn't know. He certainly never asked him who he was referring to when he had talked about Mukuro during their first meeting, or if he was actually alone as he followed their ship across the waters.

Then again, Chikusa never asked anything about him, either.

Instead, they talked about everything beyond themselves. Predictably, they bonded the most over the stars, an exchange of information as Yamamoto explained the tools he used to navigate them and Chikusa pointed out different aspects of the night sky that Yamamoto needed a spyglass to pick out. Sometimes, Yamamoto took the time to explain the craftmanship which had gone into the sword hanging from his waist- the careful inspection of the metal which it would form, the ages of hammering into the metal, the careful attention which sharpened it more than anything. He never said that it was a gift from his father, before he left home. Chikusa held no such sentimental items on his own person, in contrast. While the mer never said as much, Yamamoto could tell that, anything important to him, he had to hold inside himself. So instead of the story or creation behind any item, Chikusa simply talked about what he knew, and what he knew was one part basically the entire ocean and one part a _lot_ of incredibly embarrassing stories of what he saw humans get up to when they thought no one was looking.

Considering how he laughed hard enough to almost fall over the railing, Yamamoto nearly became one of those stories.

With that in mind, it was probably a questionable idea where Yamamoto occasionally talked to him out of the port holes inside the ship or, even worse, pulled out a small rope ladder so that he could clamber down and speak with Chikusa in a tone of voice that wasn't yelling. Every time he did it, Chikusa watched him in the careful manner one watched a cat try to walk along the rim of a full bath tub: quietly, patiently, and sort of anticipating something to laugh at. Yamamoto was proud to say he never fell.

That didn't stop Chikusa from one day saying, "I wonder how your crew would react if they realized you had fallen overboard... for just a conversation..."

"Ha ha. I bet they'd be kind of funny, although I'd feel bad." Yamamoto carefully looped his foot through the rope ladder, having to rely more on habit and touch than his ability to see. The moon gave off light, yeah, but not always enough for what humans needed. There'd be no use for torches otherwise. "But I'd be fine, right?"

"...How exactly would you be fine..."

Yamamoto grinned down at him. Even now, Chikusa still looked pale and ethereal, something that normally couldn't be touched. "Well, you would look after me if I fell into the water, wouldn't you?"

For all that they had been talking for nights, now, going into weeks, possibly edging into a month now, that idea still seemed to catch Chikusa off-guard. He stared up at him, the motion of the waves changing the eerie reflective nature of his eyes with every slight angle difference, before he slowly glanced down with his chin dipping into the water. Rather than abandoning him to the night air or outright refusing, however, he merely glanced up at Yamamoto from beneath what was sort of his hair. "You realize I'm venomous... right... I couldn't help you even if I wanted to..."

Even if he wanted to... huh? Yamamoto was silent for a second, head sort of but not really leaning against rope, while a softer smile weighed down on his lips.

"Even still. I'd trust you to figure something out." 

* * *

After the first port they stopped at, Chikusa's visits became a little less frequent. Yamamoto couldn't tell if it was because he'd gotten bored of the novelty of talking with a human, if he had friends he wanted to see, or if he had something to do like poison other ships. Maybe it was only average mer stuff. Yamamoto didn't stress over it too much. Instead, he focused on his own life with the crew: the trade, the leads, the avoiding being captured by the navy or military or anyone else that cared more about the law than the crew of the Vongola necessarily did. Occasionally at night, Yamamoto thought he saw that familiar shimmering film along the surface of the ocean when he looked out from the docks, the ship, or even town... but Chikusa didn't ever come particularly near, and so Yamamoto let him have his time on his own. Apparently, he'd been lucky with their first meeting, because it seemed to be a rare occurrence.

Sailing in open waters was a little bit better, although Chikusa still didn't appear every night as he did before. That was fine. It wasn't like Yamamoto went searching every night either, himself. Instead, their paths crossed casually, naturally, during the nighttime. In exchange, Chikusa seemed more interested to tolerate longer stretches of conversation to the point that sometimes Yamamoto himself had to leave before the mer felt bothered to. That too was somewhat comforting.

"You'll find a small island in the next day or two, if you follow your course," the mer said one night, when Yamamoto had brought out his rope ladder again for a closer talk.

Pausing where he was, Yamamoto made sure his hand was wrapped firmly in rope before he rolled his head back to look at where Chikusa was floating in the dark waters. It was good that the mer was so pale, or else he'd have a much harder time spotting him through the waves. "An island?" he echoed, thoughtful. "Is there something special about it?"

"I don't know," Chikusa said in the bored tone of someone who didn't actually care enough to look into something. "It has something that humans seem to like..."

"Ha ha, oh yeah? What is it?" No answer. Chikusa only leveled a flat and blank stare at him, and Yamamoto laughed again. "Oh yeah, I guess there's no real guarantee that you would know, even if you saw them." For all he knew, Chikusa was just passing along something he had heard. He might not have seemed like a very social person, but what did Yamamoto know? He only saw Chikusa sometimes, at night, in conversations that had nothing to do with other people. At least, not specific people, and definitely not themselves. "Well, I guess I'll just hope it's something interesting, then!"

"Who knows..." Chikusa floated in place for a brief moment, gaze sliding from side to side. Yamamoto recognized the attempt at fake casualness almost immediately. Certainly, it helped that Chikusa didn't appear to be particularly good at it. "The water is clear there..."

Yamamoto's grin creeped a little wider across his face. "Oh yeah? I thought all water is clear just because it's water?"

Whatever anyone might say about Chikusa's conversation skills- if anyone said anything at all, Yamamoto guessed- there couldn't be any denying that he was at least attentive. Yamamoto's teasing was clear as day, and he glowered a little from underneath his eyelashes. "More clear than water," he said with some reluctance, as if it was a nuisance to go along with the joke. "Similar to glass."

"Wow!" He used the exact tone of oblivious cheer that made Gokudera threaten to shove him overboard. "That sounds really impressive! I wonder if I can convince Tsuna and everyone else to drop by it for a while! It sure would be a shame not to see somewhere that sounds that nice, huh?"

Chikusa didn't deign to give him an answer. Instead, in a manner that definitely couldn't _notwas_ an island that they could almost have passed by and, true to a mer's word, the water there _was_ unbelievably clear. That much wasn't as clear when they were a good distance away from it but, the closer they got at Yamamoto's quiet but insistent nudging, the more that it couldn't be denied. It wasn't the biggest island in the world, with no signs of people that could be seen at a distance... but it didn't need to be big for its brilliant green forests to shine like a jewel in the seemingly never-ending expanse of the ocean as the vegetation creeped up a decently sized mountain in the thick of it all. That wasn't the only thing which shone, either. Once they dropped anchor a decent distance away from the island and began to take careful scouting boats nearby, even more beautiful things became apparent. Most of all was a sprawling reef that took up a good chunk of the island's shore on one side, myriads of glittering and colorful fish dipping in and out of their home. A quick glance over the island with him and Ryohei revealed that, not only was it beautiful, but the trees past the shoreline were thick with rare fruits that Gokudera was able to quickly identify. Rare, delicious, and _expensive_.

Pirates doing legitimate business was something of a laugh, honestly... but why look a gift fish in the mouth?

Unlike ships, or warehouses, or anywhere else they'd plunder before, there wasn't any need to rush off with the goods immediately. Thanks to both cautious planning from Tsuna after quite a few bad experiences and Lambo's own indulgences, they had a decent stock. Enough to take at least _one_ day, or two, to soak in the view. Besides, Yamamoto had to adjust their maps to take into consideration this island, and it would be a waste to just forget about it, right? That and a lot more were the excuses they all tried to force onto a reluctant and huffing Gokudera. It wasn't exactly a surprise that he was outnumbered, with even the girls excited for a stop like this. Eventually, grudgingly, he gave in.

Maybe it was just to stop Ryohei from following him around yelling out arguments he was just repeating from the rest of the crew.

For all that Yamamoto kept an eye out, he didn't just abandon his friends, either. The island was too beautiful to share with only one person. So he shared it with everyone who wanted to: carefully exploring from atop the reef with Tsuna, watching to make sure Lambo didn't get bit by an eel, swimming races against Kyoko, exploring the forest alongside Haru's excited chattering. Even Gokudera was having fun, he could tell. Not that he had to look hard, when he blushed so furiously as to give an apple a run for its money whenever Tsuna and Haru took him along on their fun.

...But he had to admit that something warm twisted in his chest when he looked out towards the ocean on their second and last day to see something shimmering along the surface of the ocean.

The reef didn't take up every bit of the shores along the island... just, you know, the vast majority of it. This wasn't a bad thing, as far as Yamamoto could tell. They acted as a sort of barrier between the island and the rest of the ocean, keeping the water from forming immense or particularly annoying waves. It kept the water directly around the island calm and clear, he was fairly sure. The main problem for his particular goal of the day was that, near to the shore, they were either too close together for a humanoid figure to go to or they were too shallow for something as long as a mer to get through comfortably. If it was only him, on his own, Yamamoto had no doubt that it would take him a good long while to find the perfect spot for the two of them to meet up. Fortunately, Chikusa seemed to have taken this into consideration a long time ago. Maybe even when he had first advised him of the island's existence. All Yamamoto had to do was follow that shimmering path of reflective light... up until it disappeared down into the water.

Nothing else needed to be done or said, besides Yamamoto flicking off his sandals to be abandoned into the sand. There was still a bit of reef that extended out to where he had seen Chikusa's bell disappear, although it didn't reach all the way. That was enough for Yamamoto to make his way along, until he could lean over an edge and see a humanoid figure with a long rippling lower half. A top down view didn't really give him the best look, however... So, smiling wide, he jumped right in, feet first.

At first, he couldn't see a single thing. Not past all the bubbles which burst up all around him at his actions, nor the half dozen or more fish which scattered from the sudden impact into the water. Hell, not even past his ability to see clearly in unfamiliar territory, not for a quick moment. But once he blinked his eyes a few times, the bubbles disappearing from around him... Maybe it was a good thing that, as a human, he was forced to hold his breath under water. All this time, he had only seen Chikusa at night, mostly submerged, taking in moonlight and lit up from something deep inside of himself.

In the sunlight, in clear water...? Not much else could really compare. It wasn't only the moonlight which had made him seem so silvery and shimmering. From the waist up, he could almost have been forgiven for being a pale human, if someone were drunk (not naming any names) and squinted a whole lot. Yet the eyes were still that familiar dark color, focused right on him from beneath hair that had always looked black at night. In the sunlight, it seemed to shift colors, mostly pale greens and blues with the occasional flicker of purple. The mimicry wasn't as perfectly complete in comparison to other mermaids. Eyes whose pupils weren't quite as defined, hair that seemed to move of its own accord more than in accordance with the tides, and skin that didn't seem to have quite the same depth to it as human skin... especially as it went down past where a human's pelvis would be, fading in and out with deeper shades of color lifted from his 'hair'. Where most mer had 'tails' instead of legs, Chikusa... Well. His lower half was a set of rippling frills, so long that it drifted far behind him and even past the reach of his bell. Directly underneath the sunlight and the waves, he was...

Well. Yamamoto wasn't educated enough to have the exact right word for how Chikusa looked. Just that it was sure _something_.

A suckerpunch to his lungs and heart wasn't enough to keep Yamamoto still forever. After only a second of recovering from this first proper look at Chikusa, he pushed himself forward through the water. Not too unlike that first night, perhaps it was a bit unwise to swim towards something like Chikusa. His bell was still as enormous as ever, perhaps even bigger underwater where gravity worked a little differently. The tentacles which were connected to it were about as long as Yamamoto had thought, trailing through the sea at almost the exact length of Chikusa's lower half. Even still, he didn't worry about it too much. Wasn't it only expected, when they twitched out of his way, allowing open passage past Chikusa's bell? Hold one's breath and smiling at the same time underwater was a little harder than some people thought, but Yamamoto did it anyway, drifting closer to Chikusa and anchoring himself gently with his hands around Chikusa's waist. He didn't do it too hard, too firmly. Most mer he had known throughout his life were made of sturdier stuff, their lower halves related to fish or sharks or whales that he could recognize. There was never any doubt about the... physical nature of their bodies. Whenever he'd run into jellyfish washed along the shore, however, before being ushered away by concerned adults? While their venomous nature couldn't be in doubt, they'd always seemed... particularly frail, sunk against the sands, helpless. Chikusa was certainly beautiful with the ghostly nature of his body, light shifting in easier than through any other mer or human. While he was called an idiot a lot, Yamamoto just didn't want to actually break him apart from his own lack of knowledge.

Apparently the worrying wasn't necessary. It didn't take long at all for Chikusa to pick up on how gentle Yamamoto's touch was, his brows drawing a fraction together before his hands settled over Yamamoto's. Insistently, he pressed down on the pirate's grasp. His hands were almost unbelievably soft, but they were insistent, and Yamamoto nearly laughed at the silent pushiness at play here. Sure enough, Chikusa didn't break apart like wet paper. His body merely shifted strangely, rippled, before it settled underneath his fingertips as if nothing had happened. Well, if he was good enough to be held...

Pirates had to be quick and decisive when sailing the seas... A quality Yamamoto had always held, and which he put into his personal life. So, without even a little bit of hesitation, he leaned in and slotted his lips neatly against Chikusa's mouth.

Chikusa's skin was soft as it was, deceptively fragile in both its texture and how easily Yamamoto's fingers sunk against it, and his lips were even softer. He started a little at the sudden contact, eyes wide, but he didn't move away. He only stayed where he was, stiff as much as he could be, while Yamamoto patiently pressed against him. He didn't push, didn't rush, only stayed where he was with a couple of stray bubbles rising up from the corner of his mouth. Soon enough, he felt Chikusa relax, even if only a little, before he was the one who was making his way into Yamamoto's mouth more aggressively than he'd ever displayed before. Yet the two of them weren't the same. For all that he enjoyed the feel of Chikusa's slick tongue, well, he did kind of need to breathe, and in a more literal way than how some romantic types described passionate kisses. Pulling away, Yamamoto sealed his mouth shut again and jerked his chin up towards the surface. Instead of letting him go, Chikusa shrugged and gripped Yamamoto's own waist. From within the bell, he could see the way it pulsed, curling upwards before going directly the opposite way and propelling the two of them towards the surface. He'd never pegged Chikusa as fast, but he was at least quick enough for the two of them to breach the surface sooner than later. At least he was correct in how thin the bell was, because it was certainly thin enough for him to almost immediately feel air on his face.

Promptly, he turned his head to the side and spat out some saltwater. "Ha, don't look at me like that," he said to the blurry figure that was only a few inches away from him. He didn't need to see perfectly to know that Chikusa's upper lip was curling slightly in that way it always did when he found something disgusting. "I got some of it in my mouth when I was kissing you!"

"...You didn't have to kiss me at all..."

"Did you not want me to?" Chikusa didn't immediately answer him. If anything, he actually began to slowly sink into the water, and Yamamoto pulled him back up with a laugh. "Hey, if you go too far down, your bell will hit me! Come on, come on~." Now that he'd had a few minutes to blink the water clear from his eyes, he could see Chikusa's sulking expression perfectly for all that it was as subtle as it was. "You have to be clear if you want to get something~."

"...You're a nuisance."

"Ha ha, so I've been told!"

And yet that still wasn't any kind of answer, a fact both of them knew. Yamamoto hadn't made a lot of demands of Chikusa in the time they'd known one another. Even their first meeting, that had been more of a trade off than anything, and Yamamoto had continued the trend for ages by plying Chikusa with various types of booze if he wanted to know something or merely wanted a guarantee that his ship wouldn't come under the threat of a pissed mer. For this, however? For this, he'd push a little, because it was too important for them to not know upfront where the other stood. Or... not stand. In the case of Chikusa. Well, it was a turn of phrase. Regardless. Even Chikusa seemed to understand the importance of it since, when he finally gave his answer, it was prefaced with those deep eyes slowly looking back into Yamamoto's own. "I want to touch you," he said, quiet as a dagger sliding right into Yamamoto's chest.

Yamamoto's immediate response was almost another tease, because they were certainly touching right then, weren't they? Except... He glanced down into the water, where he could see his body kicking to stay afloat. "Ha ha, whups."

"...What did you do."

"I mean, it's not really something I've done, rather, that my body did, on its own? Heh." Shameless to the very end, Yamamoto grinned. "I didn't think hearing you say that would affect me so much- whoa!" Mer could sometimes be a little bit blunt, depending on the particular race. He wasn't sure if that was true for all jellyfish mer, but it was certainly true in Chikusa's case. His hand shifted from Yamamoto's waist, drifting over the many bandanas and other similar cloths which Yamamoto liked to wrap there, and went a little more... towards the center. And down. There was no firm pressure, only a ghost of a touch to make out the bulge pressing against Yamamoto's pants, except that was somehow worse. He let out a slow shaky breath. "Uh, ha, Chikusa?"

Those dark eyes looked back up at his face again, the sunlight briefly catching them to make them see pale. "Can you even swim like this?"

"Yup!" It would be a little awkward and uncomfortable, and yet, that was something probably just about anyone experienced, growing up near the sea or any other body of water. Sometimes, you were a teenager, and sometimes, your body did really weird things. Pleasurable! But weird. "Want me to prove it?" He tilted his head backwards, looking up towards the translucent shape stretched up over them. Even this close, he wasn't entirely sure how it was attached to Chikusa. "Although I would have to dive under this, I guess."

"Don't bother." Without another word, Chikusa dipped underneath the water again... but just enough so that Yamamoto didn't smack his head into the bell. He could feel those long arms curl around his waist. That would have been fine, any other time. However, like this... Well. Certain aspects of his anatomy were definitely brushing against Chikusa, like at his shoulder. Yamamoto tried to control his breathing since, apparently that was the _only_ thing he could control. As Chikusa patiently carried him along back to shore in a surprising show of effort, he took the time to see just how it looked from the mer's point of view. He'd always wondered what it was like, looking at the world from within what was essentially a bubble. It was... pretty strange, he had to admit. The world seemed sharper, somehow, enough that it almost made his head swim a little bit. Impressive, considering that it was still tinted those same shimmering colors that had stood out to him all the nights they'd met. Did this explain how Chikusa had never seemed particularly bothered with talking to Yamamoto besides raising his voice, never explicitly needing him to climb down every night?

"Ha! You could have told me that I was putting in all that effort mostly for myself instead of helping you out, you know." If Chikusa could hear him beneath the water, there wasn't any indication that he did.

When Chikusa resurfaced, it was only after they were in shallow enough waters that Yamamoto could stand up on his own two feet. "So this is where I pick up the slack, huh?" he asked the mer, winding his arms around that fragile waist with another laugh. That expectant look on Chikusa's face said all it needed to. Well, fair was fair, and he suspected that it wouldn't be a particularly huge task anyway. Chikusa might have been more sturdy than he looked, but he was also, well. He was a jellyfish. Bracing himself against the shallows, Yamamoto grunted a little as he gathered up the mer into his arms. As far as he could tell, the main reason that Chikusa even weighed anything at all was because there was just so _much_ of him, with that frilly trail going on still into deeper waters. Trying to gather it all up into his arms would have been- well he would have had far better luck winning against Gokudera in a game of cards. Foregoing a princess style sort of carry, Yamamoto hauled him up vertically in his arms, relying on Chikusa to stay clinging to his shoulders and neck. "I'm lucky you're not similar to other mer, huh?"

Out of the water completely, and Chikusa's bell didn't have nearly as much buoyancy to it. As if to compensate in order to avoid any accidental poisonings, or maybe just make himself more comfortable, Chikusa slowly began to crawl up along Yamamot's shoulders until he was curled up near his head. Well, it was secure, that much was for sure. "What's that supposed to mean..."

"Can you imagine me hauling around a shark mer? I'm pretty strong, but not strong enough to haul that sort of person around so much!"

"Ha..." Now that was interesting. Chikusa didn't really laugh, or make laugh-like sounds, or even vaguely create noises that could distantly be related to laughter. Faintly, Yamamoto wondered if this had anything to do with someone else before the thought was promptly out of his mind as he hit the beach proper. He didn't go too far before he hoisted Chikusa up properly again so that he could flop down onto the sand without snagging his bell... or, worse, any of the many tentacles that flowed off of it. Fortunately, Chikusa seemed to have just enough control over them out of the water to keep anything from getting in the way once he realized what was happening, grunting as they fell. As usual, he didn't say anything, preferring instead to do that very slight narrowing of his eyes.

Repentance wasn't in Yamamoto's nature. He grinned some more, splayed out against the sand and hauling Chikusa a little better into position on top of him. "What? You said you wanted to touch me, right?"

There really were few things more fun than poking at the mer's stubborn and reluctant nature by calling out the obvious emotions he'd never cop to himself. Sure enough, he sunk his face down a little lower until his chin was against Yamamoto's chest where his shirt was partially open. There was that subtly sulky look again. Yet actions spoke louder than words... Without saying a single thing, Chikusa slunk a hand back down towards the bulge in Yamamoto's pants. His eyes watched the pirate intently, moving down towards Yamamoto's mouth when his breath hitched at the faintest increase of pressure. As that hand began to roam further inbetween Yamamoto's legs and up towards his belt... And _then_ Chikusa paused, frowning down at his pants.

Yamamoto needed a second before he realized what was wrong, and he couldn't stop his bark of laughter if he tried. "Having trouble with the belt?" he asked cheerfully, enjoying the way Chikusa glared down at his buckle as if that would make it disappear through sheer willpower and hatred.

"...Why are you wearing so much? I thought humans hated wearing so much clothing in the sun... And your chest isn't nearly as covered..."

"Just like how it looks," he said, which wasn't wrong. When he had his swords on him, they were handy for cleaning, impromptu bandages, temporary holders... "Need help?"

Chikusa kept up a facade of stubbornness for all of ten seconds before he let his hand flop down to the side with a huff. "I can't do it with one hand..."

A fair point, a fair point. It took a lot of dexterity to manage that kind of thing with a regular pair of pants. Add in the difficulty of a belt, and then his many bandannas... "Heh, then you might want to push yourself up. Got it?" No answer. All Chikusa did was obey quietly, hefting himself up by his palms until his body was blocking out most of the sunlight that filtered through his bell. He really looked beautiful this way, entirely different from the quiet glimpses in the night time or the full sprawling nature of his body in clear daytime water. Sunlight seemed to filter through him, colors drifting just past the pale stretch of his skin, and his eyes seemed to be an even deeper sort of purple. Yamamoto couldn't help himself; he reached upwards past the limp strands of Chikusa's hair and dragged him down for a kiss. Even outside of the water, Chikusa was soft and wet, with lips so pliable that he could stay there, sucking on them and kissing his way into his mouth, for what felt like hours. For all his quiet, for all his reserve, Chikusa clearly felt the same way. Without the use of his hands or words, he returned every single inch of affection with a focused and steady passion.

It still wasn't exactly as breathless as literally running out of air under the water was, but it was enough to have Yamamoto pleasantly flushed when he finally pulled away. "Hah. Wow. Ha ha, I hope your hair isn't like the tentacles."

"...Take off your pants already."

Well, he couldn't blame him for the rush- not with Yamamoto's crew members around somewhere, and not with how a mer was undeniably an aquatic creature and could only spend so much time on land. So he did his best to not get distracted again, as difficult as that was with Chikusa literally being right on top of him, and craned his neck so that he could look properly down at his pants. Taking _everything_ off just seemed kind of silly, not to mention impossible when he'd have to move Chikusa off of him first. Undoing the front would have to be enough... and it definitely _felt_ like enough when he let his arousal out into open air. Cool water combined with the sudden intense lack of restriction sent a shudder trembling throughout his whole body, and Yamamoto's head fell back into the sand with an exhilarated rush of air. That... That was much better. Yet not nearly as better as when Chikusa, not content to let him enjoy just a brief moment of freedom, slid his fingers against the length of him, prompting another shiver. Lube, water, saliva- none of it compared to the slick and temptingly smooth surface of the mer's palm as he wasted no time in circling his fingers around Yamamoto's cock.

And yet that wasn't where his attention was. Chikusa spared only a moment to enjoy the novelty of seeing a human dick, palm slow and exploratory, before he was looking directly back into Yamamoto's eyes. Chikusa's fingers were, above all else, _experimental_ as he stroked and rubbed, pumped and slid, his finger all across his arousal. His dick, he realized, was really only a tool at the end of the day. A means to an end. What Chikusa was much more interested in, he quickly realized, were his reactions. Every twitch, what drew out gasps in contrast to moans, how his eyelashes would flutter at a particular slow twist of his fingers. How long had he been planning this encounter out? With how slowly Chikusa moved sometimes, Yamamoto couldn't help but fantasize that it had been ages.

He wanted to dig his fingers into something, anything, but the sand was unsatisfying with how it slipped through his grasp so easily. At some point, he realized he had raised one hand up to brace against Chikusa's hip, and he realized this because that's when the mer looked away from his face to where his fingers were placed. They were right where a human's pelvis bone would have pressed out at and, for Chikusa, the start of where pale 'skin' began to become a little more thin in favor of color that would become all the more brilliant in the frills that stretched out past Yamamoto's feet.

"Not as easy to make you feel good, huh?" he breathed out, voice husky as he watched Chikusa let go of his arousal to lay his hand over Yamamoto's again. It hadn't really occurred to him, at least in depth, until just now. "Although I guess we can keep kissing-"

He tore through Chikusa's skin.

It was hard to say if he moved his thumb wrong, if Chikusa pressed down too hard with his own hand, or what. It probably didn't matter. All that mattered was that it had happened, that faint feel of resistance against his nail before he realized that his thumb had dipped in far more than it should have against something physical.

Yamamoto stared down for a second, a little bit stunned and somehow still with an erect dick despite himself. "Oh," he said numbly before he laughed again- his incurable habit that popped up during the worst moments most of the time.

In contrast, Chikusa didn't seem even remotely worried. As a matter of fact, he didn't even seem to be in _pain_ at all. He only blinked down at the scene, Yamamoto's thumb partially through a paper thin slice into his would-be pelvis before giving what could arguably be called a nod. "This should work."

Chikusa moved his hand out of the way, and Yamamoto let him. He had seen a lot of weird shit in his life. In fact, occasionally, he was the one responsible for the weird shit in question. However, this was an entirely new experience, even for him, and so all he could say was, "Ha ha, work for what, exactly?"

A blank blink. "Humans... have sex like this, don't they? They stick a part of themselves into the hole of the other person..."

Yamamoto had always kind of assumed that everything had sex that way, but the ocean _was_ pretty strange, so he let that pass by him. Instead, he took a moment to really think on that. "I mean, there's definitely a lot of sexual acts, I guess? And people are always making new ones, ha ha, so I was willing to be creative when it came to you." And he had assumed that he was going to have to be pretty creative in this particular sort of situation. Finally, he raised his hand again, a lot more soft as he ghosted his fingertips along the skin near to where the slit now was. "Are you okay? You didn't have to do that."

"It's fine." Chikusa was a little more insistent in pulling Yamamoto's hand this time, although there was still no sign of pain, true enough. Rather, he seemed almost more _embarrassed_ than anything, dipping his chin down towards his chest slightly. It wasn't obvious, but it was a tell that Yamamoto had come to learn. "Now hold still."

Well, if he was certain. Yamamoto did as he was told, eyes trained on Chikusa while the mer carefully adjusted himself over his prone body. Chikusa said he wasn't in pain, so he would trust him on that fact... and he couldn't help but be curious as well. From the angle he was looking at and the small size of the slit, he couldn't really see just what was beneath the 'skin' of such a mer. All he could do was rely on his sense of touch, letting his eyes fall shut as Chikusa delicately began to lower his body down onto him. Even only a bit of his dick inside was enough to make him hiss, surprised at the utterly foreign sensation. The inside of Chikusa's body was too soft, too flexible, too _much_ to be anything even remotely human. Yamamoto couldn't think of any other similar sensation. Soft ridges curved along his cock, so slick that the strange formation of them sucked him right in but firm enough that he couldn't slip out so easily. There was no question of if Chikusa could take him in fully, their bodies pressed fully against one another. Labored breathing directly before him forced Yamamoto to open his eyes, where he found himself face to face with the mer. There was no other way to be, not when they were joining in a way like this, where Chiksua was forced to lower himself. And this close... No, maybe even from a distance, Yamamoto would be able to see the blush that had blossomed across his face. Mer blushed like humans blushed, most of the time, but being something so foreign as a jellyfish seemed to change things. Instead of red, or pink, or even orange, Chikusa flushed a pale blue that crawled along his throat and jawline from the exertion of just lowering himself down onto Yamamoto's body.

That answered that. Still shivering from this new form of pleasure, he reached up to brace his hands against Chikusa's hips to help steady him. "I guess I don't have to worry about if you're enjoying the moment or not."

Chikusa's eyes flickered up to him from beneath half-lidded lashes. "...Shut up..." Breathing unsteadily himself, he raised his body up even as it still tried to cling to Yamamoto's cock. With his hands at his hip, he did his best to help the mer rise until just the very tip was still inside.

"Want help? I know you hate moving more than you ever need to."

"I just said..." There was no need to repeat himself. Chikusa let his actions do the talking for him, falling back onto Yamamoto's arousal so swiftly that he couldn't stop the way his hips bucked into that soft wet hole. His head rolled back, following the moan that came out of his mouth. When he opened his eyes again, Chikusa was near to his face again, but this time his eyelashes were dipped in a quiet but undeniably smug satisfaction. "Shut up."

"Bossy," Yamamoto breathed, smiling. Still, he could be good. It was worth it to roll his hips up against Chikusa's again and watch the mer duck his head down, shuddering in a way that couldn't be missed with the way they were right up against one another. Under the heat of the beach sun, it was a blessing to have the mer so close to him like this, and even the inside of his body seemed to warm up just enough to be comfortable. To be perfect. It was slow, almost a little awkward, as they adjusted to the strange position... but Yamamoto knew how to figure things out. Chikusa let him, even. While they couldn't go at breakneck speed, rutting like animals on the land would... Somehow this was almost more preferable. This was a mirror of their entire relationship, both with each other and the ocean that connected them so much: slow, steady, rolling into each other again and again until the cool quiet of everything began to steadily rise into an unbearable heat. Even with the way Yamamoto's body throbbed, aching for release, he kept careful. Chikusa was sturdy and delicate in equal measure, something that required an even more delicate hand than if he was only one or the other...

And, besides. This way, he got the perfect view of Chikusa slowly falling more and more into pleasure, jaw trembling with each attempt at holding back any sounds of arousal, his flush turning his skin a blue to match his lower half, and the way his insides constricted and twitched all around his cock. It was a torment onto him, too, but he considered it a price well paid for getting to see Chikusa in a way that he'd never seen him before. Wringing out a soft keen of pleasure, seeing the way he finally dug his fingers not into the sand but Yamamoto's shoulders, all while his body shook in the telltale way of release... That was enough for him, too.

Laying there in the afterglow, Chikusa sunk contentedly against his body while colors shifted through the bell that was still held over them, was enough for him. 

* * *

"I knew we couldn't have a nice time without someone doing something stupid," Hana said, exhausted and deadpan right from the get-go. Most of the crew was gathered around where Yamamoto had been propped up against the side of the railing, in varying degrees of Fuss (tm). "Alright, so, what happened?"

Numb throughout most of his body but apparently not enough to really kill him (yet), Yamamoto laughed out one side of his mouth. "Ha ha, so, how do you know if something is poisonous?"

"He _fucked a jellyfish_, Kurokawa!" Gokudera snarled out with zero prompting, before anyone could beat him to the punch.

Silence rolled over the deck. Finally, Hana raked her fingers through her hair before pointing accusingly at where Tsuna was knelt down at Yamamoto's other side. "I swear to _God_ I am leaving this fucking crew."

"Please don't," Tsuna said weakly, for all that he looked as extremely exasperated and tired as Hana did. Being the captain and doctor respectively was an unenviable task on a regular ship. The Vongola somehow made that all the more difficult. "You're the only doctor we have, or I think can even find?"

"I'm not even supposed to be a doctor!" Groaning, Hana came over and promptly shoved Gokudera out of the way with clear disregard for his squawks of protest. For all her complaining, she didn't hesitate in kneeling down besides Yamamoto and quickly doing some quick basic tests for his vitals. "I was reading up on law, damn it! How did I even end up with you bunch of idiot men!?" No one said anything about how Kyoko was sitting there right there with them all, even when she reached over to cheerfully pat Hana's shoulder. "Yamamoto, you absolute dumbass, a jellyfish?"

"I mean, it wasn't a literal jellyfish!" Yamamoto protested, patiently enduring the poking and prodding. It wasn't as though he had any other choice in the matter. "It was a mer. Who happened to be part jellyfish."

"That's only nominally better," she grumbled, checking his breathing. As far as Yamamoto could tell, it wasn't too severe a poisoning, or else his body would be going through a lot worse right now. He'd seen the effects of a jellyfish sting a couple of times in his life, and more often heard the horror stories. He wasn't throwing up, his lungs were still working, and he was quite proud to say that his bowels weren't going out of control. "As in, we can at least say it was consensual or I would be guessing you wouldn't even have made it back to the ship."

"No need to worry there!"

Yet it didn't escape him that he was getting a good dose of heavy inspection from some of the other crew members- notably Haru, Ryohei, and Lambo. All of them stayed respectfully quiet while Hana did her inspection, at least for how long it would take for her to confirm on if Yamamoto would kick the bucket in the next twenty four hours. Once the amount of time passed where it was clear that Hana wouldn't break out into swearing and panic, Yamamoto could see the way all of them glanced over at him in ways that ranged from subtle to... not so much.

Haru was the one who won on being more subtle, batting her eyelashes innocently. "I've never heard of jellyfish mer before, you know. They must not interact with humans a lot, right?"

"Ha ha, I guess not, although the one I know just seems naturally shy!" Which was sure a word to describe Chikusa, but hey.

"Maybe you can introduce us sometime!"

"No one is meeting the jellyfish Yamamoto fucked!" Gokudera snarled.

"Ha ha, I don't think that's really up to you, Gokudera?"

"So was it a good fling?" Lambo asked suddenly, foregoing any tact as usual to ask the question that was _really_ on more than a few people's minds.

Tsuna dragged his hands down along his face at around the same time Hana pinched the bridge of her nose, looking as though she was five seconds away from tossing them all overboard and raising the anchor herself. Gokudera swung an accusatory finger around towards Lambo. "What did I just say!?" he snapped, ignoring the relieved way Ryohei clenched a fist that someone had asked before him.

"You said we couldn't meet him, not that I couldn't ask!"

"No one wants to hear about Yamamoto's sex life!"

"I just asked, _I_ want to hear!"

Yamamoto thought about the light filtering through Chikusa's body, the multitude of little changes that spokes volume in his often stoic expression, how he'd rested so comfortably along Yamamoto's chest. "Ha. It was pretty great."

"Nice-"

"What the fuck did I just say, you god damn idiot-"

"When it comes to him, I would like to think that 'pretty great' is the very least he could do."

That... wasn't a voice from any of them, and they all paused to look towards the opposite side of the ship. None of them said anything, none of them immediately attacked, but Yamamoto could see the more subtle adjustments, especially from his own technically vulnerable position. Tsuna adjusted himself nearer to Yamamoto, one hand braced against his shoulder and rising up just enough so that he had a better view of the deck itself and anything that might come from their side of the ship. Hana and Lambo both stayed low, the doctor herself readying against Yamamoto's other side much like Tsuna was braced. Leaning just a little bit more in front of him was Ryohei, eternally bandaged fists already partially formed and his attention sharp. Kyoko looked a lot more deceiving, peering innocently over her brother's shoulder, which always seemed to catch people off every time. Better than Haru, whose hands were none too subtly positioned over her flintlock pistols, and loads better than Gokudera who already had a small bomb rolling around in one of his fingers.

The person hanging off the side of their ship didn't seemed particularly concerned despite all this. They only grinned, lazy and self confident in a way that seemed to have a little more weight to it than none at all. Yamamoto could discern that sort of thing. It was a useful skill to have, both out on the seas and in the more rough taverns that catered to pirates or at least didn't chase them off. Then again, perhaps part of that feeling was also because there was only one sort of person who would show up in the middle of the ocean. And for that kind of person... Of course they could wear a smile like that, mismatched eyes detached and cool for all the potential danger. "This is quite a welcome," they drawled lazily, reaching up to tuck some hair back into the spiky ponytail they had drawn back. Even with only a small portion of their upper body visible, it was clear that this one had a taste for decoration. The direct opposite of the often bare Chikusa, honestly. Every movement had the various bracelets on his wrist click together. "Shouldn't you be a little more polite, considering how much I could help you?"

Gokudera leaned over just enough so that he could hiss at Yamamoto from the corner of his mouth. "This better not be the jellyfish you fucked."

"Nope."

Among all of them, Gokudera was pretty good at being quiet when bossing them around... and yet that mismatched stare still managed to flick in his direction. "Maybe not the exact person you're looking for," he said, reaching down to something on the side of the ship, "but certainly someone who can help you out with your... very unique predicament." With that, he raised up a small vial from inbetween his fingers. "While I doubt it's anything _lethal_, it would still be better to have the antidote on hand, wouldn't it?"

Hana perked up immediately. "You have an actual antitode for _jellyfish venom_?" From behind Ryohei, Kyoko delicately pressed her hands against her brother's back and rose up a little onto her feet in curiosity.

Their fun new visitor rolled the vial about between deft fingers. "Jellyfish mer venom. And only for this particular sting. It's all very unique, isn't it? Especially with..." They broke into soft chuckles. "Well, we can speak about that another time."

Gokudera, never one for the finer aspects of negotiation or bartering, twitched one eyebrow. "Are you going to give us the god damn thing or keep talking?" By this point, Kyoko was more properly on her feet and had taken a few steps around Ryohei, leaning to the side and blinking innocently.

"Are you really in such a rush? I think by this point you can tell well enough that the dosage of venom he has isn't lethal... but that doesn't mean it's a pleasant experience, is it?" They rolled their shoulders in an elegant shrug, and tossed their head to the side. "You can think of this as a minor token of good will-"

"Oh, then thank you so much!" Before anyone could even blink, Kyoko was across the ship with her hands around the vial and then halfway back. Even their visitor needed a second to blink. While everyone else just... absorbed Kyoko's decisiveness, she dropped down by Hana's side and presented the vial with a smile that befitted a seaside maiden instead of a pirate. Yamamoto sort of wanted to laugh again. "Here, Hana!"

"Aww, thanks, Kyoko." Hana flashed her a smile that immediately contrasted with the disgusted look she gave everyone else besides the literally poisoned person. "At least someone here isn't useless, which is more than I can say for the rest of you, including the mer!"

"What about me?"

"...Haru, you're still a little bit of a weirdo, but you get a pass."

Quickly covering up their surprise, the mer leaned back and shrugged with his hands flicking to the side. "My, what an interesting group. Chikusa really did pick something interesting this time. Well, as I said- consider it a gift. But I'll be certain to pay you a visit soon for... compensation."

While Gokudera let out a string of swears, Yamamoto did his best to smile. It was somewhat difficult, considering the circumstances, but he did his best with what he had. "Well, thanks for being such a nice guy to pay us a visit! Hopefully I'll be more chatty then, ha ha. See you later, Mukuro."

Their eyebrows slowly raised, intrigued, before he let out another low laugh. "I can see why he took to you. Well. I'll be taking my leave." And with that, he pushed himself off, only the slightest glimpse of his octopus bottom half visible before he disappeared out of sight.

Under the sound of the waves, Gokudera dragged one hand down his face. "I absolutely hate," he said, "the shit you get up to when no one is keeping an eye on you." 

* * *

"It went well," Mukuro said airily as he ducked down towards the reef bottom, ignoring the many fish around him in much the same way that most of them ignored him. "I can tell they'll be quiet useful in the future."

Almost immediately, Ken stopped circling Chikusa impatiently and went straight towards Mukuro, shark fin cutting through the water smoothly. "I knew it would be easy for you, Master Mukuro!" he crowed, bright eyed and encouraging as always. For the attention, Mukuro indulged him, and ran one hand along from Ken's hair to his fin.

Ignoring the happy wiggling underneath his palm, he focused his gaze onto Chikusa. It was hard to the point of impossibility to not burst out laughing, instead keeping his voice level as he murmured, "He didn't seem to be poisoned particularly badly. Still, I suppose there is some due credit in the... daring of his particular choice in partners."

Ken was a lot less subtle, bearing his teeth and sniggering at his partner as he circled around Mukuro once again to face him. "You poisoned the guy who tried to fuck you!" he howled. "I would have loved to see the look on his face when he realized what had happened!"

No answer was forthcoming from Chikusa. All he did was float there, arms crossed and his tentacles wound about him in a protective spiral. It was the most defensive a mer of the jellyfish could possibly get, with how it made getting through the gaps a lot harder than if they were spread out normally. Mukuro didn't let that deter him, instead pushing himself forward and floating just out of reach with a smirk on his face. "Was he that good?" he said, hardly keeping the mocking out of his voice. "To lose control of your venom like that?"

Still no answer, just a nudge of his chin downwards towards his shoulder. Mukuro laughed softly again, but let it rest. If Chikusa liked that human so much, maybe Mukuro would keep him alive. At least, until his subordinate got over the feel of human hands.

It would happen eventually, he was sure.

* * *

**Author's note**: This was written way back when for the KHR Rarepair Week of 2019, as sort of bonus content. Over on tumblr and ao3, I made graphics for all the quick fics I'd made... but I was torn on what ship to do for the mer/pirate prompt. I really wanted to write both Aria/the Cervello and Yamamoto/Chikusa, but I couldn't choose which to actually do. In the end, I went with Aria/Cervello because I could easier make a graphic for them... but I still really wanted to write something for Yamamoto/Chikusa.

And that's where we're at with this!

don't fuck jellyfish, kids


End file.
